Caltech News tagged with "engineering"http://www.caltech.edu/news/tag_ids/23/rss.xml
enProgrammable Disorderhttp://www.caltech.edu/news/programmable-disorder-53104
<div class="field field-name-field-subtitle field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Random Algorithms at the Molecular Scale</div></div></div><div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Lori Dajose</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/LQian_DNATilings-NEWS-WEB.jpg?itok=Kjk6p-Wj" alt="image of self-assembled random tree structures on the surface of DNA tile arrays" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Colored atomic force microscope image of self-assembled random tree structures on the surface of DNA tile arrays. Each tree has a single loop as the “root”.</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Caltech / Grigory Tikhomirov, Philip Petersen and Lulu Qian</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>Many self-organized systems in nature exploit a sophisticated blend of deterministic and random processes. No two trees are exactly alike because growth is random, but a Redwood can be readily distinguished from a Jacaranda as the two species follow different genetic programs. The value of randomness in biological organisms is not fully understood, but it has been hypothesized that it allows for smaller genome sizes—because not every detail must be encoded. Randomness also provides the variation underlying adaptive evolution.</p><p>In contrast to biology, engineering seldom takes advantage of the power of randomness for fabricating complex structures. Now, a group of Caltech scientists has demonstrated that randomness in molecular self-assembly can be combined with deterministic rules to produce complex nanostructures out of DNA.</p><p>The work, done in the laboratory of Assistant Professor of Bioengineering <a href="https://www.bbe.caltech.edu/content/lulu-qian">Lulu Qian</a>, appears in the November 28 issue of the journal <em>Nature Nanotechnology.</em></p><p>Living things use DNA to store genetic information, but DNA can also be used as a robust chemical building block for molecular engineering. The four complementary molecules that make up DNA, called nucleotides, bind together only in specific ways: A's bind with T's, and G's bind with C's. In 2006, Paul Rothemund (BS '94), research professor of bioengineering, computing and mathematical sciences, and computation and neural systems at Caltech, invented a technique called DNA origami that takes advantage of the matching between long strands of DNA nucleotides, folding them into everything from nanoscale artwork to drug-delivery devices. The self-assembled structures formed through DNA origami may be functional by themselves or they may be used as templates to organize other functional molecules—such as carbon nanotubes, proteins, metal nanoparticles, and organic dyes—with unprecedented programmability and spatial precision.</p><p>Using DNA origami as a building block, researchers have made larger DNA nanostructures, such as periodic arrays of origami tiles. However, because the building block is just repeated everywhere, the complexity of patterns that can be formed on these larger structures is quite limited. Entirely deterministic assembly processes—controlling the design of each individual tile and its distinct position in the array—can give rise to complex patterns, but these processes do not scale up well. Conversely, if only random processes are involved and the global features of the array are not controlled by design rules, it is impossible to create complex patterns with desired properties without simultaneously generating a large fraction of undesired molecules that are wasted. Until the work by Qian and her colleagues, combining deterministic processes with random ones had never been systematically explored to create complex DNA nanostructures.</p><p>"We were looking for molecular self-assembly principles that embrace both deterministic and random aspects," says Qian. "We developed a simple set of rules that allow DNA tiles to bind randomly but only into specific controlled patterns."</p><p>The approach involves designing patterns on individual tiles, modulating the ratios of different tiles, and determining which tiles can bind together during self-assembly. This leads to large-scale emergent features with tunable statistical properties—a phenomenon the authors dub "programmable disorder."</p><p>"The structures that we can build have programmably random aspects," says Grigory Tikhomirov, a senior postdoctoral scholar in biology and biological engineering, and lead author on the paper. "For example, we can make structures that have lines that take seemingly random paths, but we can ensure that they never intersect and always eventually close up into loops."</p><p>In addition to loops, the team chose two other examples, mazes and trees, to demonstrate that many nontrivial properties of these structures can be controlled by simple local rules. They found these examples interesting because loop, maze, and tree structures widely exist in nature across multiple scales. For example, lungs are tree structures at the millimeter to centimeter scale, and neural dendrites are tree structures at the micrometer to millimeter scale. The controlled properties that they showed include the branching rules, the growth directions, the proximity between adjacent networks, and the size distribution.</p><p>The group was first inspired by the classic Truchet tiles, which are square tiles with two diagonally symmetrical arcs of DNA on the surface. There are two rotationally asymmetrical orientations of the arc pattern (see image below). Allowing a random choice of the two tile orientations at each location in the array, the pattern will continue through neighboring tiles, either becoming loops of various sizes or exiting from an edge of the array.</p><div style="width:600px; margin:0 0 0 7px; color:#000000; padding:2px; border:0px solid black; font-size:0.85em; line-height:1em;"><img alt="ALT" src="https://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/Truchettiles.jpg" title="TITLE" width="600" /> Left, Truchet tiles have two arcs that are rotationally asymmetrical. Right, popular board games inspired by Truchet tiles. <span style="color:#636363; font-size:0.85em;"><em>(credit: Courtesy of L. Qian)</em></span></div><p>To create Truchet arrays at the molecular scale, the team used the DNA origami technique to fold DNA into square tiles and then designed the interactions between these tiles to encourage them to self-assemble into large two-dimensional arrays.</p><p>"Because all molecules bump into each other while floating around in a test tube during the process of self-assembly, the interactions should be weak enough to allow the tiles to rearrange themselves and avoid being trapped at any undesired configurations," says Philip Petersen, a graduate student in the Qian laboratory and co-first author on the paper. "On the other hand, the interactions should be specific enough so the desired interactions are always much preferred over undesired, spurious interactions."</p><p>Different types of global patterns emerge when tiles are marked with different local patterns. For example, if each randomly oriented tile carries a "T" rather than two arcs, the global pattern is a maze with branches and loops rather than only loops (see images below). If the self-assembly rules constrain the possible relative orientation of neighboring "T" tiles, it is possible to ensure that other than a single "root," the branches in the mazes never close into loops—producing trees. To explore the full generality of these principles, Qian's team developed a programming language for random DNA origami tilings.</p><div style="width:600px; margin:0 0 0 7px; color:#000000; padding:2px; border:0px solid black; font-size:0.85em; line-height:1em;"><img alt="ALT" src="https://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/qian-loops_and_mazes.jpg" title="TITLE" width="600" /> Self-assembled loop, maze, and tree structures on the surface of DNA tile arrays. Top row, random mazes with three-way and four-way junctions of varying distances between adjacent junctions versus only three-way junctions of a fixed distance between adjacent junctions. Middle row, random trees (each tree has a single loop as the "root") with longer branches of varying lengths versus shorter branches of fixed lengths. Bottom row, random loops with tunable lengths and number of crossings. <span style="color:#636363; font-size:0.85em;"><em>(credit: Courtesy of L. Qian)</em></span></div><p>"With this programming language, the design process starts with a high-level description of the tiles and arrays, which can be automatically translated to abstract array diagrams and numerical simulations, then moves to DNA origami tile design including how the tiles interact with each other on their edges. Finally, we design DNA sequences," Qian says. "With these DNA sequences, it is straightforward for researchers to order the DNA strands, mix them in a test tube, wait for the molecules to self-assemble into the designed structures overnight, and obtain images of the structures using an atomic force microscope."</p><p>The group's method of programmable disorder has diverse future applications. For example, it could be used to build complex testing environments for ever-more-sophisticated molecular robots—DNA-based nanoscale machines that can move on a surface, pick up or drop off proteins or other kinds of molecules as cargos, and make decisions about navigation and actions.</p><p>"The potential applications are much broader," Qian adds. Since the 1990s, random one-dimensional chains of polymers have been used to revolutionize chemical and material synthesis, drug delivery, and nucleic acid chemistry by creating vast combinatorial libraries of candidate molecules and then selecting or evolving the best ones in the laboratory. "Our work extends the same principle to two-dimensional networks of molecules and now creates new opportunities for fabricating more complex molecular devices organized by DNA nanostructures," she says.</p><p>The paper is titled <a href="http://resolver.caltech.edu/CaltechAUTHORS:20161012-163039195">"Programmable disorder in random DNA tilings."</a> This work was funded by the National Science Foundation, a National Institutes of Health National Research Service Award, and the Burroughs Wellcome Fund.</p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://www.caltech.edu/news/programming-dna-molecular-robots-interview-lulu-qian-40808" class="pr-link">Programming DNA for Molecular Robots: An Interview with Lulu Qian</a></div><div class="field-item odd"><a href="http://www.caltech.edu/news/students-try-their-hand-programming-dna-46996" class="pr-link">Students Try Their Hand at Programming DNA</a></div><div class="field-item even"><a href="http://www.caltech.edu/news/team-led-caltech-wins-second-10-million-award-research-molecular-programming-40276" class="pr-link">Team Led by Caltech Wins Second $10 Million Award for Research in Molecular Programming</a></div><div class="field-item odd"><a href="http://www.nature.com/nnano/journal/vaop/ncurrent/full/nnano.2016.263.html" class="pr-link">Nature News and Views: DNA origami tiles - Nanoscale mazes</a></div></div></div>Mon, 28 Nov 2016 19:49:11 +0000ldajose53104 at http://www.caltech.eduGPS Innovator Charles Trimble Receives von Kármán Wings Awardhttp://www.caltech.edu/news/gps-innovator-charles-trimble-receive-von-k-rm-n-wings-award-53039
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Robert Perkins</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/CharlesTrimble-2016-VonKarmanWingsAward-32-NEWS-WEB.jpg?itok=m52PG0WV" alt="Award presentation" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Charles Trimble receives the von Kármán Wings Award from Mory Gharib</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Amelia Tabullo </div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>Caltech senior trustee Charles Trimble (BS '63, MS '64), founder and former chief executive officer of Trimble Navigation, Ltd., is the 2016 recipient of the <a href="http://www.galcit.caltech.edu/ahs">International von Kármán Wings Award</a>. The honor—administered by the Aerospace Historical Society and the <a href="http://www.galcit.caltech.edu/">Graduate Aerospace Laboratories of the California Institute of Technology (GALCIT)</a>—recognizes Trimble's "visionary leadership contributions to the aerospace industry, and distinguished service to the nation's defense and aerospace programs," according to the <a href="http://www.galcit.caltech.edu/ahs/program/">award announcement</a>.</p><p>Through the launch of Trimble in 1978, Charles Trimble led the industry in developing commercial equipment that utilizes the Global Positioning System (GPS). By the late '90s, the company was a leading worldwide supplier of GPS equipment. Since leaving Trimble in 1998, he has mentored several entrepreneurs and served on the boards of directors for public and private companies. He also sits on the Caltech Board of Trustees.</p><p>"GPS as an information technology has been a disruptive force in changing the way people live and work. The space-based infrastructure that has made this possible is a shining example of this country's aerospace achievements," Trimble says. "I am honored and humbled to be associated with aerospace legends such as William Pickering, Si Ramo, Buzz Aldrin, Dan Goldin, Charles Elachi, and many others."</p><p>Mory Gharib, the Hans W. Liepmann Professor of Aeronautics and Bioinspired Engineering at Caltech, director of GALCIT, and chair of the Aerospace Historical Society presented the award at a private banquet at the Athenaeum on November 17. </p><p>"In addition to his pioneering contributions to GPS commercialization, Charlie has had a big impact on Caltech and JPL," Gharib says. "As an alumnus and trustee, he deeply understands the needs of Caltech and serves the community with dedication and insight."</p><p>Trimble is the recipient of numerous awards and honors, including <em>Inc</em>. magazine's Entrepreneur of the Year in 1991, the American Electronics Association Medal of Achievement in 2000, the NASA Public Service Medal in 2001 and 2004, and the Caltech Distinguished Alumni Award in 1995. In 1994, he received the Piper General Aviation Award from the American Institute of Aeronautics and Astronautics for pioneering the manufacture and application of affordable GPS. </p><p>Also at the banquet, Gharib presented the Shirley Thomas Academic Scholarship to Caltech graduate student Yuchen Wei from the lab of Sergio Pellegrino, the Joyce and Kent Kresa Professor of Aeronautics and professor of civil engineering; Jet Propulsion Laboratory Senior Research Scientist; and co-director of the Space-Based Solar Power Project. Wei is contributing to the hardware and software development of an autonomously assembled and reconfigurable space telescope design. In a written statement read by Gharib at the banquet, Pellegrino described Wei as "a tireless and passionate researcher who is making the most of his time at GALCIT."</p><p>Every year since 2010, the Shirley Thomas Academic Scholarship has been presented to a student in aerospace, aeronautics, or a related program who demonstrates promise for continued contribution to the field. Thomas, the founder of the Aerospace Historical Society, was an actress, writer, producer, and professor who became a prominent figure in the early days of the space program. She authored more than 15 books, including an eight-volume series on astronauts titled <em>Men of Space</em>.</p><p>This was the 32nd annual International von Kármán Wings Award ceremony. Since its inception in 1985, the Aerospace Society has honored luminaries such as astronaut Buzz Aldrin (1994), science fiction writer Arthur C. Clarke (2001), private spaceflight pioneer Burt Rutan (2005), and, of course, Theodore von Kármán (posthumously, 1991).</p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://www.caltech.edu/news/trimble-named-caltech-trustee-622" class="pr-link">Trimble Named Caltech Trustee</a></div></div></div>Sun, 20 Nov 2016 01:26:16 +0000rperkins53039 at http://www.caltech.eduRemembering Rolf Sabersky, 1920‑2016http://www.caltech.edu/news/remembering-rolf-sabersky-1920-2016-53003
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Robert Perkins</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/Sabersky%2C%20R%5B2%5D.jpg?itok=vI7fdTQC" alt="Rolf Sabersky" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Rolf Sabersky, 1977</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: <a href="http://archives.caltech.edu">Caltech Archives</a> (photo by Floyd Clark)</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>Rolf Sabersky, professor of mechanical engineering, emeritus, died on October 24. He was 96 years old.</p><p>Sabersky made pioneering contributions to our understanding of boiling heat transfer, free convection, granular flows, and indoor air quality. He taught courses in thermodynamics, fluid mechanics, and heat transfer.</p><p>Sabersky earned his bachelor's, master's, and PhD degrees in mechanical engineering from Caltech in 1942, 1943, and 1949, respectively. He joined the faculty of the Division of Engineering and Applied Science (EAS) as an assistant professor in 1949, became associate professor in 1955, and was named professor in 1961. He retired in 1988.</p><p>He was preceded in death by his wife of 70 years, Bettina, who died five months before his passing. Friends and family describe Sabersky as a devoted family man with a gentle manner and a wry sense of humor; colleagues note that he was a gifted teacher and a mentor to students and junior faculty members alike. </p><p>"Rolf was just a wonderful person who wanted me to succeed and for my colleagues to succeed," says Melany Hunt, Dotty and Dick Hayman Professor of Mechanical Engineering, who first met Sabersky when she joined Caltech as an assistant professor in 1988. </p><p>Born on October 20, 1920, in Berlin, Sabersky attended the Französisches Gymnasium, a French high school founded by the Huguenots in 1689, until he was 17 years old. A few months after his graduation in the spring of 1938, he and his family, who were devoted Jews, emigrated to the United States from Germany.</p><p>"We didn't realize how late it was," Sabersky said in <a href="http://oralhistories.library.caltech.edu/131/1/OH_Sabersky.pdf">a 1990 interview at Caltech</a>. "Soon thereafter, November '38, the so-called Kristallnacht took place."</p><p>Sabersky, along with his parents, brother, and sister, stopped first in Switzerland, then went to Los Angeles, where Sabersky had been accepted as a student at Caltech. There, he became a member of Dabney House. "From '39 on, I've been here ever since, every day," he said in the 1990 interview. "Pretty much every day of my life, I've been on campus since that day."</p><p>The bombing of Pearl Harbor during his senior year brought the war to the United States, and suddenly Sabersky—who was not yet a citizen—was legally an "enemy alien." A group of students organized to guard the campus, which housed several war-related projects. Sabersky joined the group but, because of his citizenship status, he was deemed unable to participate as a guard. Instead, he volunteered as the group's secretary until the student-run group was replaced by professional guards. Later, as a graduate student, Sabersky joined the campus's civil defense unit as a member of the fire brigade, alongside J. E. Wallace Sterling, who would go on to become the director of the Huntington Library and Art Gallery and then the president of Stanford University.</p><p>After earning his master's degree, Sabersky took his one professional turn outside of academia, accepting a job offer from Aerojet, a rocket and missile propulsion manufacturing company that had been founded by Theodore von Kármán in 1942. At the time, von Kármán was the director of what was then called the Guggenheim Aeronautical Laboratories of the California Institute of Technology (GALCIT), and so the nascent company—which resided in an automobile agency near campus that had been left vacant by the war—included many faculty and students from the Institute. At Aerojet, Sabersky worked on the development of sustained-duration liquid-rocket engines, building personal and professional connections that would last for the rest of his career. Decades later, he met with former Aerojet colleagues for regular lunches at the Athenaeum.</p><p>Sabersky met his future wife, Bettina Schuster, while visiting his sister Lore at the University of California, Berkeley, where Bettina was a graduate student studying romance languages. Like Sabersky, Bettina had been born in Germany but ended up in California after fleeing the Nazis.</p><p>In 1946, with the war over, the newly married Sabersky returned to Caltech and resumed his studies. In 1949, he received a PhD in mechanical engineering for his work on axial flow compressors, which use spinning airfoils to continuously pressurize gases. The compressors are still used today in jet engines.</p><p>Over his career, Sabersky made pioneering contributions to our understanding of boiling heat transfer, free convection, granular flows, and indoor air quality—work for which he received the Heat Transfer Memorial Award from the American Society of Mechanical Engineers in 1977. In particular, his research focused on what he described as "funny fluids"—materials such as ketchup, which have complicated flow characteristics that manufacturers are keen to understand. He was the author of two popular textbooks, <em>Elements of Engineering Thermodynamics</em>, and <em>Fluid Flow: A First Course in Fluid Mechanics</em>, which he coauthored with Allan Acosta, Richard L. and Dorothy M. Hayman Professor of Mechanical Engineering, Emeritus.</p><p>Sabersky taught courses in thermodynamics, fluid mechanics, and heat transfer for nearly four decades at Caltech, and was beloved by his students—in 2011, former students organized a dinner in his honor. He was equally appreciative of them and of Caltech, Hunt says. "He was ever grateful to Caltech for everything that Caltech had done for him, and he wanted to pass that along."</p><p>Sabersky is survived by his two daughters, Carol and Sandy, and their families.</p></div></div></div>Wed, 16 Nov 2016 19:17:09 +0000rperkins53003 at http://www.caltech.eduRolf Sabersky, 1920-2016http://www.caltech.edu/news/rolf-sabersky-1920-2016-52947
<div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/Rolf_Sabersky-1977-credit_Floyd_clark.jpg?itok=-hZrFz5t" alt="photo of Rolf Sabersky" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Rolf Sabersky, 1977</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: <a href="http://archives.caltech.edu">Caltech Archives</a> (photo by Floyd Clark)</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>Rolf H. Sabersky, Caltech professor of mechanical engineering, emeritus, passed away on October 24, 2016, at the age of 96. </p><p>Born on October 20, 1920, in Berlin, German, Sabersky earned his bachelor's, master's, and PhD degrees in mechanical engineering from Caltech in 1942, 1943, and 1949, respectively. He joined the Caltech faculty as an assistant professor in 1949, became associate professor in 1955, and was named professor in 1961. He retired in 1988.</p><p>Sabersky made pioneering contributions to our understanding of boiling heat transfer, free convection, granular flows, and indoor air quality. He taught courses in thermodynamics, fluid mechanics, and heat transfer.</p><p>Throughout his career, Sabersky worked with numerous luminaries, including Theodore von Kármán at Aerojet. James Van Allan sought his expertise for the development of the Ajax and Bumblebee rocket programs. </p><p>At Caltech, Sabersky was renowned for his commitment to education, mentoring, and promoting diversity. He was the author of two popular textbooks, <em>Elements of Engineering Thermodynamics</em>, and <em>Fluid Flow: A First Course in Fluid Mechanics</em>, which he coauthored with Caltech's Allan Acosta, the Richard L. and Dorothy M. Hayman Professor of Mechanical Engineering, Emeritus. He received the Heat Transfer Memorial Award from the American Society of Mechanical Engineers in 1977.</p><p>Sabersky was preceded in death by his wife of 70 years, Bettina, and is survived by his two daughters, Carol and Sandy, and their families.</p><p>Note: A <a href="/news/remembering-rolf-sabersky-1920-2016-53003">longer obituary</a> was posted on November 17, 2016.</p><p> </p></div></div></div>Fri, 11 Nov 2016 00:39:53 +0000rperkins52947 at http://www.caltech.eduRealistic Solar Corona Loops Simulated in Labhttp://www.caltech.edu/news/realistic-solar-corona-loops-simulated-lab-52867
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Robert Perkins</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/Ha-Bellan-GRL-highlight-NEWS-WEB.jpg?itok=u9-vsSES" alt="Coronal loop" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Side-by-side: A real coronal loop (left) compared to one simulated in Paul Bellan&#039;s lab (right).</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Courtesy of P. Bellan/Caltech</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>Caltech applied physicists have experimentally simulated the sun's magnetic fields to create a realistic coronal loop in a lab.</p><p>Coronal loops are arches of plasma that erupt from the surface of the sun following along magnetic field lines. Because plasma is an ionized gas—that is, a gas of free-flowing electrons and ions—it is an excellent conductor of electricity. As such, solar corona loops are guided and shaped by the sun's magnetic field.</p><p>The earth's magnetic field acts as a shield that protects humans from the strong X-rays and energized particles emitted by the eruptions, but communications satellites orbit outside this shield field and therefore remain vulnerable. In March 1989, a particularly large flare unleashed a blast of charged particles that temporarily knocked out one of the National Oceanic and Atmospheric Administration's geostationary operational environmental satellites that monitor the earth's weather; caused a sensor problem on the space shuttle <em>Discovery</em>; and tripped circuit breakers on Hydro-Québec's power grid, which caused a major blackout in the province of Quebec, Canada, for nine hours.</p><p>"This potential for causing havoc—which only increases the more humanity relies on satellites for communications, weather forecasting, and keeping track of resources—makes understanding how these solar events work critically important," says <a href="http://www.eas.caltech.edu/people/2927/profile">Paul Bellan</a>, professor of applied physics in the Division of Engineering and Applied Science.</p><p>Although simulated coronal loops have been created in labs before, this latest attempt incorporated a magnetic strapping field that binds the loop to the sun's surface. Think of a strapping field like the metal hoops on the outside of a wooden barrel. While the slats of the barrel are continually under pressure pushing outward, the metal hoops sit perpendicularly to the slats and hold the barrel together.</p><p>The strength of this strapping field diminishes with distance from the sun. This means that when close to the solar surface, the loops are clamped down tightly by the strapping field but then can break loose and blast away if they rise to a certain altitude where the strapping field is weaker. These eruptions are known as solar flares and coronal mass ejections (CMEs).</p><p>CMEs are rope-like discharges of hot plasma that accelerate away from the sun's surface at speeds of more than a million miles per hour. These eruptions are capable of releasing energy equivalent to 1 billion megatons of TNT, making them potentially the most powerful explosions in the solar system. (CMEs are not to be confused with solar flares, which often occur as part of the same event. Solar flares are bursts of light and energy, while CMEs are blasts of particles embedded in a magnetic field.)</p><p>The simulated loops and strapping fields provide new insight into how energy is stored in the solar corona and then released suddenly. Bellan worked with Caltech graduate student Bao Ha (MS '10, PhD '16) to create the strapping field and coronal loop. The results of their experiments were published in the journal <em>Geophysical Research Letters</em> on September 17, 2016.</p><p>Bellan and his colleagues have been working on laboratory-scale simulations of solar corona phenomena for two decades. In the lab, the team generates ropes of plasma in a 1.5-meter-long vacuum chamber.</p><p>"Studying coronal mass ejections is challenging, since humans do not know how and when the sun will erupt. But laboratory experiments permit the control of eruption parameters and enable the systematic explorations of eruption dynamics," says Ha, lead author of the <em>GRL</em> paper. "While experiments with the same eruption parameters are easily reproducible, the loop dynamics vary depending on the configuration of the strapping magnetic field."</p><p>Simulating a strapping field with strength that fades over the relatively short length of the vacuum chamber proved difficult, Bellan says. In order to make it work, Ha and Bellan had to engineer electromagnetic coils that produce the strapping field inside the chamber itself.</p><p>After more than three years of design, fabrication, and testing, Bellan and Ha were able to create a strapping field that peaks in strength about 10 centimeters away from where the plasma loop forms, then dies off a short distance farther down the vacuum chamber.</p><p>The arrangement allows Bellan and Ha to watch the plasma loop slowly grow in size, then reach a critical point and fire off to the far end of the chamber.</p><p>Next, Bellan plans to measure the magnetic field inside the erupting loop and also study the waves that are emitted when plasmas break apart.</p><p>Their paper is titled <a href="http://resolver.caltech.edu/CaltechAUTHORS:20160826-092807478">"Laboratory demonstration of slow rise to fast acceleration of arched magnetic flux ropes."</a> The research was supported by the National Science Foundation, the Air Force Office of Scientific Research, and the U.S. Department of Energy Office of Science, Office of Fusion Energy Sciences.</p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://eas.caltech.edu/news/490" class="pr-link">Solar Loops and Space Weather</a></div><div class="field-item odd"><a href="https://www.youtube.com/watch?feature=player_profilepage&amp;v=Z2QLx_ERzao" class="pr-link">Video: Pasmas Torn Apart</a></div></div></div>Fri, 04 Nov 2016 18:39:58 +0000rperkins52867 at http://www.caltech.eduPractical Mathematics: An Interview with Andrew Stuarthttp://www.caltech.edu/news/practical-mathematics-interview-andrew-stuart-52808
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Robert Perkins</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/AStuart-Caltech-9427-NEWS-WEB.jpg?itok=qcTpckFi" alt="Andrew Stuart" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Andrew Stuart</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Credit: Caltech</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p><em>New Caltech faculty member <a href="http://www.cms.caltech.edu/people/5854/profile">Andrew Stuart</a> is interested in how the current era of data acquisition interacts with centuries of human intellectual development of mathematical models that describe the world around us. As an applied mathematician in the Division of Engineering and Applied Science (EAS), he generates the mathematical and algorithmic frameworks that allow researchers to interface data with mathematical models. His work is informed by—and has applications for—diverse arenas such as weather prediction, carbon sequestration, personalized medicine, and crowd forecasting. Originally from London, Stuart earned his bachelor's degree at Bristol University and then a combined master's/PhD at Oxford University. He worked as a postdoc at MIT in the late '80s, as a lecturer at the University of Bath in England from 1989 to 1992, and then as professor at Stanford University and the University of Warwick in England. He relocated to Southern California this summer. Recently, Stuart answered a few questions about his research and his new life at Caltech.</em></p><h3>What brought you to Caltech?</h3><p>The high quality research in engineering and applied science as well as the high quality of undergraduate and graduate students. I'm excited by the opportunity to develop my mathematical research in new directions, both in terms of applications and in terms of underpinning mathematical methodologies. There's an undeniable beauty to pure mathematics, but what has always driven my interests in mathematics is the potential for diverse applications, and the role of mathematics in unifying these different fields. Caltech provides enormous potential for collaboration in areas of interest to me, in the EAS and Geology and Planetary Sciences divisions for example, and also at JPL.</p><h3>For example?</h3><p>Weather forecasting. Netwon's laws, describing conservation of mass, momentum and energy, in principle have enormous predictive power. But lack of precise knowledge of the initial state of the atmosphere, together with physical effects on scales too small to resolve efficiently on the computer, mean that the "butterfly effect" (in which small changes in complex systems ultimately yield major effects) can lead to poor forecasts. Data provides a potential resolution to this problem, or at least an amelioration of it. Right now we have satellites, aircraft, and weather balloons all collecting vast amounts of data; figuring out how best to use these data can substantially improve the accuracy of our forecasting. A lot of good applied mathematics is about formulating the right problems, as well as finding algorithms for solving them.</p><h3>How did you get into your field?</h3><p>I grew up in an academic household; I saw that it was a challenging, stimulating, and intellectually rewarding career. My dad, who worked at Imperial College in fluid mechanics, loved his job and I was very aware of this. I then developed an excitement for mathematics that grew once I started majoring in the field as an undergraduate student.</p><h3>What are you looking forward to about being in Southern California?</h3><p>The great combination of urban culture and outdoors life. I enjoy cinema, art, reading novels, and hiking. Recently I have been to Kings Canyon and Sequoia, and I have also visited MOCA (Museum of Contemporary Art) Grand Avenue. </p></div></div></div>Thu, 27 Oct 2016 19:53:52 +0000rperkins52808 at http://www.caltech.eduStudy: Raising Temperature Changes an Element's Electronic "Topology"http://www.caltech.edu/news/study-raising-temperature-changes-elements-electronic-topology-52809
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Robert Perkins</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-png view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/Screen%20Shot%202016-10-27%20at%2012.55.12%20PM.png?itok=vwnFJ9Fl" alt="Fermi surface" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">A Fermi surface for FeTi, showing the allowable energy states that can be occupied by electrons.</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Courtesy of Fred Yang and Brent Fultz</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>Materials scientists at Caltech have discovered a new way that heat tweaks the physical properties of a material.</p><p>Experimenting with an alloy of iron and titanium (FeTi), a team led by Caltech's <a href="http://www.eas.caltech.edu/people/3016/profile">Brent Fultz</a> found that increasing heat alters the topology of the material's Fermi surface—an abstract map of the allowable energy states that can be occupied by electrons.</p><p>Fultz, the Barbara and Stanley R. Rawn, Jr., Professor of Materials Science and Applied Physics in the Division of Engineering and Applied Science, likens a Fermi surface to a planet covered by a smooth ocean and rocky landmasses. The ocean is made up of electrons, while the land represents voids where electrons are not present. Placing an element under extreme pressure—like that in Earth's core—can cause landforms lurking just below the surface to emerge, in turn altering where electrons are likely to be found. The appearance of these new features in a Fermi surface is called an electronic topological transition (ETT). The concept of an ETT was proposed by the Russian physicist I. M. Lifshitz in 1960, and ETTs have been observed by subjecting metals to pressures on the order of 100,000 atmospheres.</p><p>Heating causes electrons to slosh around within the Fermi surface, but, as with waves moving on water, the coastlines—the boundaries between electrons and electron-less voids—remain about the same. However, Fultz and his colleagues noticed that because heat also displaces atoms, heating can in some cases reveal landforms hidden below the surface of that metaphorical Fermi sea.</p><p>In practical terms, altering the topology of the Fermi surface alters the chemical properties of a metal or alloy, which in turn alters its electrical conductivity.</p><p><!--MEDIA-WRAPPER-START-3--><img alt="Fermi surface GIF" class="media-element file-default" data-file_info="%7B%22fid%22:%2213157%22,%22view_mode%22:%22default%22,%22fields%22:%7B%22format%22:%22default%22,%22field_file_image_alt_text%5Bund%5D%5B0%5D%5Bvalue%5D%22:%22Fermi%20surface%20GIF%22,%22field_caption%5Bund%5D%5B0%5D%5Bvalue%5D%22:%22The%20electronic%20topology%20of%20FeTi%20changing%20as%20temperature%20is%20increased.%22,%22field_file_image_title_text%5Bund%5D%5B0%5D%5Bvalue%5D%22:%22%22,%22field_photo_credit%5Bund%5D%5B0%5D%5Bvalue%5D%22:%22Courtesy%20of%20Fred%20Yang%20and%20Brent%20Fultz%22%7D,%22type%22:%22media%22%7D" src="https://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/ANIMATION-Fultz-GIF-10-25-16.gif" style="height: 325px; width: 400px; float: right;" /><!--MEDIA-WRAPPER-END-3--><!--MEDIA-WRAPPER-END-2--><!--MEDIA-WRAPPER-END-1--></p><p><attachment webkitattachmentpath="/Users/rperkins/Desktop/ANIMATION-Fultz-GIF-10-25-16.gif"></attachment>The potential value to engineers lies in the fact that it is much easier to raise the temperature of a material than it is to place it under the sort of pressure needed to force an ETT. "The pressures needed to cause an ETT are intense, while the temperature changes needed are comparatively low," says Fultz. Indeed, gigapascals of pressure are required to cause an ETT—that is, tens of thousands of times the pressure of Earth's atmosphere. However, Fultz and his colleagues noted ETTs occurring within hundreds of degrees Fahrenheit of temperature change.</p><p>The discovery was something of an accident—the result of computationally chasing down anomalous results while performing neutron scattering tests on an FeTi alloy that is of interest to engineers because it is remarkably strong and stretchable.</p><p>Neutron scattering reveals details about a material's atomic structure. In the method, a beam of neutrons is fired at a material and the energies and angles of the scattered neutrons are recorded and analyzed. In particular, Fultz's group was using neutron scattering to study the vibrations of atoms in crystals, which almost always move and buzz slightly. The researchers found that, with increasing temperatures, the specific patterns of buzzing changed dramatically in a way that could not be explained through known mechanisms.</p><p>Caltech graduate student Fred Yang (MS '15), lead author of a paper about the discovery appearing in the journal <em>Physical Review Letters</em>, ran numerous computer simulations that suggested the temperature-related change could be explained by an ETT in FeTi.</p><p>Next, Fultz and Yang plan to explore other elements with features lurking just below their Fermi surfaces.</p><p>Their paper, titled <a href="http://resolver.caltech.edu/CaltechAUTHORS:20160808-113911118">"Thermally Driven Electronic Topological Transition in FeTi,"</a> was published by <em>Physical Review Letters</em> on August 8. Coauthors include Olle Hellman, a visitor in applied physics and materials science at Caltech; former Caltech graduate students Jorge Muñoz (MS '09, PhD '13), Lisa Mauger (MS '10, PhD '15), Matthew Steven Lucas (MS '05, PhD '09), and Sally June Tracy (MS '11, PhD '16); Matthew Stone and Doug Abernathy of Oak Ridge National Laboratory; and Yuming Xiao of the Carnegie Institution for Science.</p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://www.caltech.edu/news/how-iron-feels-heat-45656" class="pr-link">How Iron Feels the Heat</a></div></div></div>Thu, 27 Oct 2016 20:05:32 +0000rperkins52809 at http://www.caltech.eduThird Round of BRAIN Fundinghttp://www.caltech.edu/news/third-round-brain-funding-52766
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Lori Dajose</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/BRAIN-Initiative-2016-NEWS-WEB_0.jpg?itok=FKdWdDXT" alt="Design of brain" /><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Shutterstock</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>On October 13, the National Institutes of Health (NIH) announced its third round of funding for President Obama's Brain Research through Advancing Innovative Neurotechnology (BRAIN) Initiative. More than 100 new awards were given, totaling just over $150 million, nearly doubling the NIH's investment in the BRAIN Initiative. This year, six Caltech researchers have received funding for their projects studying the brain.</p><p><strong>"Neuronal Substrates of Hemodynamic Signals in the Prefrontal Cortex"</strong></p><p style="margin-left:.5in;"><em><a href="https://www.hss.caltech.edu/content/john-p-odoherty">John O'Doherty</a>, </em><em>professor of psychology; Director, Caltech Brain Imaging Center</em></p><p style="margin-left:.5in;"><em><a href="https://www.bbe.caltech.edu/content/doris-y-tsao">Doris Tsao</a> (BS '96), </em><em>professor of biology; Investigator, Howard Hughes Medical Institute</em></p><p>Along with Matthew Howard of the University of Iowa and Daeyeol Lee at Yale University, O'Doherty and Tsao received a grant from the National Institute of Mental Health (NIMH) to study the relationship between neuronal signals and fMRI responses in the prefrontal cortex during value-based decision making.</p><p><strong>"Dexterous BMIs for tetraplegic humans utilizing somatosensory cortex stimulation"</strong></p><p><em> <a href="https://www.bbe.caltech.edu/content/richard-andersen">Richard Andersen</a>, </em><em>James G. Boswell Professor of Neuroscience</em></p><p>Andersen received funding from the National Institute of Neurological Disorders and Stroke (NINDS) to develop a neural prosthetic to assist tetraplegic patients to dexterously control a robotic hand with recorded brain signals. Research collaborators include Charles Liu of University of Southern California and Mindy Aisen from Rancho Los Amigos National Rehabilitation Center.</p><p><strong>"Deep brain photoacoustic tomography at single-neuron resolution using arrays of photonic emitters and high-frequency ultrasound transducers"</strong></p><p style="margin-left:.5in;"><a href="http://www.eas.caltech.edu/people/5770/profile"><em>Lihong </em></a><em><a href="http://www.eas.caltech.edu/people/5770/profile">Wang</a>, </em><em>Bren Professor of Medical Engineering and Electrical Engineering</em></p><p style="margin-left:.5in;"><em><a href="https://pma.caltech.edu/content/michael-l-roukes">Michael Roukes</a>, </em><em>Robert M. Abbey Professor of Physics, Applied Physics, and Bioengineering</em></p><p>Along with Kenneth Shepard of Columbia University, Wang and Roukes received a grant from NINDS to develop an advanced high-speed, high-resolution nanoprobe-based imaging technology based on high-frequency photoacoustic computed tomography that will enable observation of the structure and activity deep in small animal brains with single-neuron resolution.</p><p><strong>"Wide deployment of massively multiplexed nanosystems for brain activity mapping"</strong></p><p style="margin-left:.5in;"><em>Michael Roukes, </em><em>Robert M. Abbey Professor of Physics, Applied Physics, and Bioengineering</em></p><p>Roukes and Kenneth Shepard of Columbia also received funding from NINDS to develop sophisticated neural nanoprobe systems to enable exploration of the dynamics of brain circuits in many species, through highly multiplexed electrical stimulation and recording of neural activity, local chemical sensing of neuromodulators, and optogenetic stimulation of brain circuits at the cellular scale.</p><p><strong>"Molecular Functional Ultrasound for Non-Invasive Imaging and Image-Guided Recording and Modulation of Neural Activity"</strong></p><p><em> <a href="https://www.cce.caltech.edu/content/mikhail-g-shapiro">Mikhail Shapiro</a>, </em><em>assistant professor of chemical engineering</em></p><p>Along with coinvestigators Richard Andersen and Mickael Tanter of ESPCI in Paris, Shapiro received funding from NINDS to develop improved ultrasound techniques to monitor neural activity.</p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://www.caltech.edu/news/nih-announces-second-round-brain-funding-48135" class="pr-link">NIH Announces Second Round of BRAIN Funding</a></div><div class="field-item odd"><a href="http://www.caltech.edu/news/caltech-researchers-receive-nih-brain-funding-43895" class="pr-link">Caltech Researchers Receive NIH BRAIN Funding</a></div><div class="field-item even"><a href="http://www.caltech.edu/news/nsf-brain-funding-awarded-caltech-neuroscientist-47517" class="pr-link">NSF BRAIN Funding Awarded to Caltech Neuroscientist</a></div></div></div>Mon, 24 Oct 2016 20:33:36 +0000ldajose52766 at http://www.caltech.eduNoise-Canceling Opticshttp://www.caltech.edu/news/noise-canceling-optics-52593
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Robert Perkins</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/CYang-AnimGIF-NEWS-WEB-Final_Frame.jpg?itok=VUj9ykgV" alt="image of the results of glare suppression" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Destructive interference cleans up an image to make text legible.</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Edward Zhou/Caltech</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>Engineers at Caltech have created the visual analogue of noise-canceling headphones—a camera system that can obtain images of objects obscured by murky media, such as fog or clouds, by canceling out the glare.</p><p>When you drive through fog, objects on the road are difficult to see because the light from your headlights is mostly scattered back at you by particles in the fog—a phenomenon called "glare." This effectively masks the objects that are dimly reflective.</p><p>A team led by Caltech's <a href="http://eas.caltech.edu/people/3261/profile">Changhuei Yang</a> and Edward Zhou created a device that selectively cancels the scattered light, leaving only the light that is reflected or bounced off the objects and has slipped back through the murk unmolested. The new system relies on destructive interference to do the canceling. Light has wavelike properties, and so superimposing one beam of light over another beam that has peaks where the first has troughs—and vice versa—will cancel out both beams.</p><p>"The idea that we can directly cancel glare is new," says Yang, professor of electrical engineering, bioengineering, and medical engineering in the Division of Engineering and Applied Science, and the senior author of a paper on the new technology, termed "coherence gated negation" (CGN), published on October 5 by the research journal <em>Optica</em>.</p><p>CGN splits a laser into twin parallel beams, using one to illuminate a target and the other to cancel out the glare. Superimposing the light from each results in a cleaned-up image on a camera sensor.</p><p><img align="left" src="https://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/CYang-AnimGIF-NEWS-WEB.gif" style="margin-right: 20px; margin-top: 7px" width="250" />To test the device, Yang and Zhou placed a line of text behind a one-millimeter-thick block of glass beads suspended in a gel, rendering the text completely illegible. Then, using CGN, they were able to boost the contrast of the text by a factor of about 30—producing an image that, while not perfectly clear, is legible.</p><p>CGN has numerous potential uses, including for the satellite exploration of cloud-obscured planets like Venus. It also has biomedical applications, offering a noninvasive way to optically examine tissues under the skin. "Optically, our skin behaves very similarly to a dense fog. CGN can be used to cancel the tissue glare and allow us to see through the skin," says Edward Zhou, graduate student at Caltech and lead author of the <em>Optica</em> paper.</p><p>The new system may also someday help drivers to navigate foggy roads, although the speed of the image resolution would need to be improved significantly. "A very nice aspect of this method is that there is a fairly straightforward approach for increasing its speed by several orders of magnitude. Wouldn't it be nicer <em>and</em> safer if you can see the whole San Francisco bridge as you drive across it on a foggy day?" says Yang.</p><p>The <em>Optica</em> study, titled "Glare Suppression by Coherence Gated Negation," can be found online at <a href="http://resolver.caltech.edu/CaltechAUTHORS:20161010-124426959">http://resolver.caltech.edu/CaltechAUTHORS:20161010-124426959</a>. Zhou and Yang's coauthors include Caltech graduate students Atsushi Shibukawa, Joshua Brake, and Haowen Ruan. This work was supported by the National Institutes of Health, a Gwangju Institute of Science and Technology–Caltech Collaborative Research Proposal, the National Institute of Biomedical Imaging and Bioengineering, and the Donna and Benjamin M. Rosen Bioengineering Center. </p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://www.caltech.edu/news/seeing-inside-tissue-4209" class="pr-link">Seeing Inside Tissue</a></div><div class="field-item odd"><a href="http://www.caltech.edu/news/new-technique-makes-tissues-transparent-1380" class="pr-link">New Technique Makes Tissues Transparent</a></div></div></div>Mon, 10 Oct 2016 16:56:14 +0000rperkins52593 at http://www.caltech.eduCaltech Offers Open Online Course on Quantum Cryptographyhttp://www.caltech.edu/news/caltech-offers-open-online-course-quantum-cryptography-52456
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Robert Perkins</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/Vidick-Thomas_6349-NEWS-WEB.jpg?itok=w3ajQ3Gn" alt="photo of Thomas Vidick" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Thomas Vidick, Assistant Professor of Computing and Mathematical Sciences</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Lance Hayashida/Caltech Office of Strategic Communications</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>This summer, Caltech's <a href="http://eas.caltech.edu/people/5373/profile">Thomas Vidick</a> spent a month delivering a series of lectures about quantum cryptography… to an empty room. On October 9, students around the world will be able to enjoy them.</p><p>Vidick, assistant professor of computing and mathematical sciences in the Division of Engineering and Applied Science, is participating in a massive open online course (MOOC) that will be available, along with two other courses from Caltech, to thousands of students through the <a href="https://www.edx.org/school/caltechx">edX online education platform</a>.</p><p>The class—<a href="https://youtu.be/DERsAtboQ5k">CS/Ph 120, Quantum Cryptography</a>—is cotaught by Vidick and his longtime colleague Stephanie Wehner from QuTech at the Delft University of Technology. Both Vidick and Wehner also will have classroom components to their courses, at their respective institutions.</p><p>Vidick says that he was inspired to teach the course through conversations with his PhD advisor at Berkeley, Umesh Vazirani, who taught a MOOC titled "Quantum Mechanics and Quantum Computation."</p><p>Vidick's course focuses on the ways in which quantum mechanics can be used to create secure lines of communication. Though the concept was first proposed in the 1970s, it has only recently gone mainstream, with the first quantum bank transaction taking place in 2004.</p><p>"It's a hot topic, but there are very few resources for people wanting to go beyond just the basics. Very few schools will even have a quantum cryptography course," Vidick says.</p><p>So far, CS/Ph 120 has 5,500 registered students—small, by the standards of MOOCs, which average 43,000 students, according to a 2014 study by a researcher at the Open University in the United Kingdom. Even so, Vidick expects that just about 200 will stick out the program to the end, given that the average completion rate for MOOCs sits around 6.5 percent.</p><p>For the dozen or so Caltech students and 40 Delft students who will attend in-person, the class will use the "flipped classroom" model, in which the lectures are done online, with time in the classroom spent cementing what the students have learned and diving deeper into the concepts.</p><p>While no prior knowledge of quantum mechanics is necessary, students will need to have a strong grasp of linear algebra, a branch of mathematics central to engineering, in order to follow along, Vidick says. "Making the course accessible does not mean dumbing it down, and the less mathematically inclined might find it challenging," he cautioned in a recent post to his <a href="https://mycqstate.wordpress.com/2016/09/09/coming-to-a-theater-near-you/">personal blog</a>, announcing the course.</p><p>The edX course launches on October 9, although in-class students already have begun meeting, to go over the basics of linear algebra, quantum information, computer science, and cryptography—concepts that will be used throughout.</p><p>Online, students will have access to video lectures, lecture notes, quizzes, and links to additional resources.</p><p>This will be Vidick's first MOOC and his first time teaching quantum cryptography—but he says he is looking forward to the challenge.</p><p>"Every time I finish teaching a class I want to teach it again right away, because it's like <em>'Now</em> I know how to do it,'" Vidick says.</p><p>Students can enroll online at <a href="https://www.edx.org/course/quantum-cryptography-caltechx-delftx-qucryptox">https://www.edx.org/course/quantum-cryptography-caltechx-delftx-qucryptox</a>.</p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="https://youtu.be/DERsAtboQ5k" class="pr-link">Quantum Cryptography | CaltechX and DelftX on edX | Course About Video</a></div></div></div>Wed, 28 Sep 2016 19:33:22 +0000rperkins52456 at http://www.caltech.edu